Odontopleurid trilobites of the Katian/Hirnantian boundary interval in the Prague Basin (Bohemia)

A new association of odontopleurid trilobites is described from calcareous claystone to marlstone, the so-called Pernik Bed, of the topmost part of the Kraluv Dvur Formation. The association includes Diacanthaspis krizi sp. nov., associated with Bojokoralaspis peregrina (Barrande, 1872) and other rare and poorly known odontopleurids preliminary referred to Chlustinia Pribyl & Vanek, 1965, Proceratocephala Prantl & Pribyl, 1949 and Eoleonaspis Sheng, 1974. This association indicates a closer relationship to the late Katian and early Hirnantian odontopleurid faunas of Baltica and Avalonia than to those of Armorica (Spain, Sardinia), where the genera Calipernurus Whittington, 1956a, Diacanthaspis Whittington, 1941, Dicranurus Conrad, 1841, Hispaniaspis Hammann, 1992, Radiaspis Richter& Richter, 1917, and Whittingtonia Prantl & Pribyl, 1949 are present in carbonatic buildups of the late Katian age. It is assumed that the deposition of Pernik Bed is a result of the early Hirnantian sea level lowering and not of the warming related to the Boda event.